MARS SCIENCE LAB WEATHER PROBLEMS
$2.5 Billion Worth of Childish Mistakes By Mars Science Laboratory Weather "Experts." (Mostly posted on 10/18/2012; but updated on 9/29/2014).
It's bad enough that NASA farmed out its Mars Science Laboratory (MSL) weather mission to a foreign (Spanish and Finnish) group at the Centro de Astrobiologia. On October 19, 2012 I wrote that foreigners can't seem to put out a weather report that makes any sense. On August 30, 2012, over three weeks after the MSL landed on Mars, the first air pressure measurements were published. For the dates of August 28, 29, and 30, the pressures were a little lower than the accepted normal, just 7.4 hPa (millibars) compared to an average Earth pressure of 1,013.25 hPa. It looked like the absurdly low pressures of the Vikings, Mars Pathfinder and Mars Phoenix that my son and I have argued against for the past two years as speakers at the International Mars Society conventions:
| PowerPoint Summary of HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE - Part 1 by David A. Roffman. Posted August 31, 2012. |
| PowerPoint Summary of PART 2 (Annexes and Supporting Data for HIGHER THAN ADVERTISED MARTIAN AIR PRESSURE): Posted August 18, 2011. |
But on September 2, 2012, the pressure published for September 1, 2012 at http://cab.inta-csic.es/rems/marsweather.html rose from 7.4 hPA to an astounding 742 hPa, which is 73.2% of Earth's average pressure at sea level. This is the equivalent of saying one day that the air outside is almost nonexistent like we find on Earth's moon, and saying the very next day that it's actually like what we would experience at 8,368 feet (2,550 meters). You can safely drive far above that height in many places in the U.S. The 742 hPa figure is probably an error in which the web site manager forgot to convert 742 Pascals to 7.42 Hectopascals, however it is also what I think the real pressure is there. My son disagrees. He thinks it's higher still due to dust devils (seen here moving across the Martian surface) and spiral storms seen on and over a mountain named Arsia Mons (see Figures 4 and 5). The Remote Environmental Monitoring Station (REMS) report commentary on Figure 1 indicates the pressure went from lower than normal to higher than normal, but it might be calculating what average is now only in reference to the previous 4 published pressures for MSL. The web site does not explain its data.
9/29/2014 Update: Two years after I wrote the above I cannot only state that the weather reporting from MSL remained a disaster for most of the first year, but that even after the exceedingly sloppy mistakes were fixed (in many cases as a result of what I pointed out to JPL's public relations director Guy Webster), the data that I didn't succeed in getting JPL to pull down or alter, remains absolutely unbelievable. My son and I got JPL to pull down all winds. We also got them to use our calculated sunrise and sunset times for MSL a Gale Crater. I can now estimate pressure at Mars areoid to be about 511 mbar, not the 6.1 mbar that NASA still advocates. To understand how JPL and NASA continued to screw up for the past two years see the updated PowerPoint here. See slide 12 for how the 511 mbar estimate was derived. Also see Section 12.3 of our updated report here. A PDF of the full Basic Report, dated July 22, 2014, is located here.
Figure 1: The REMS Team put out a wrong Mars calendar at first. It was fixed, but then they published highly dubious pressure data with pressure units (hPa vs. Pa) that look like a mistake............................... Figure 2 below shows that if anyone wanted to guess at what pressure would be expected when Mars was at Ls 162 in its orbit, 7.4 hPa (which equals 7.4 millibars) would be a safe bet based on Viking data, even if totally wrong. 742 hPa, however, makes perfect sense in terms of the weather seen on Mars. 7.4 hPa makes no sense at all.
Figure 3 below shows an impossible pressure increase over three days - from 7.4 to 742 hPa. This is probably due to an error at REMS with a decimal place, or their confusion between pressure units of Pa (Pascals) and hPa (hecto Pascals). It was corrected to Pa after we brough the error to their attention.
Reis et al. (2009) suggest a greenhouse-thermophoretic (GT) effect that they believe explains ~1 mbar dust lifting at Arsia Mons. Their article states that “Laboratory and microgravity experiments show that the light flux needed for lift to occur is in the same range as that of solar insolation available on Mars.” They concede that high altitude dust devils do not follow the season of maximum insolation, but indicate that the GT-effect would be strongest around pressures of 1 mbar. However, if anything we would expect such dust lifted at high altitude to just drift away. The GT effect simply does not explain the structure of these events at high altitude, or why the dust rotates in columns that precisely match dust devils produced at lower altitudes. Further, Figure 1 shows that dust devils form at successively lower levels (i.e., higher pressures) as altitudes decline from 17 km to about 7 km, so there is nothing unique about reaching the ~1 mbar-level at the top of Arsia Mons. But the strange weather in Arsia Mons does not stop with the dust devils.
Figure 4 - Dust devils on Arsia Mons at an altitude of 17 km (10.625 miles) above Mars areoid.
SPIRAL CLOUDS SEEN OVER ARSIA MONS. As seen on Figure 5, the Jet Propulsion Laboratory states that:
Just before southern winter begins (in the Southern hemisphere where Arsia Mons is located), sunlight warms the air on the slopes of the volcano. This air rises, bringing small amounts of dust with it. Eventually, the rising air converges over the volcano's caldera, the large, circular depression at its summit. The fine sediment blown up from the volcano's slopes coalesces into a spiraling cloud of dust that is thick enough to actually observe from orbit. The spiral dust cloud over Arsia Mons repeats each year, but observations and computer calculations indicate it can only form during a short period of time each year. Similar spiral clouds have not been seen over the other large Tharsis volcanoes, but other types of clouds have been seen... The spiral dust cloud over Arsia Mons can tower 15 to 30 kilometers (9 to 19 miles) above the volcano. (NASA/JPL/MSSS, 2005, PIA04294).
Figure 5 shows structures analogous to the eye walls of small hurricanes associated with these spiral clouds. They are about 10 km across and appear quite vigorous. These pictures were taken just before the southern winter when planetary pressures should be approaching minimums. At such high altitude, there should not be enough pressure differentials to drive such storms.
Figure 5 - Spiral storms with 10 km-wide eye walls over Arsia Mons. These storms makes no sense if pressure at the summit is only about 1 hPa/mbar.
FIGURE 6A to 6D - Daily pressure and temperature fluxuations are shown with pressures in Pascals and temperature in Pascals. The hypothesis with the Vikings was that when it got colder outside, the RTG heaters pumped more heat into the area around the pressure transducers. Air trapped behind a clogged dust filter then saw its pressure rise as the heat was applied. When the RTG heat was no longer shipped there, the pressure fell. A first look at sol 10 suggests something like this might hav happened again. This will need to be related to initial confusion about methane detected by the SAM. It turned out that it was not Martian air, but rather it was trapped terrestrial air.
FIGURE 7 - Pressures and temperatures for Figures 6A to 6D were taken from below. The temperature graph was created with data acquired on August 16/17. Ground Temperatures vary from as high as 3 degrees Celsius to as low as minus 91°C showing a large gradient from day to night. Air temperature reached a maximum of minus 2°C and decreased to minus 75 degrees at night. The image shows that ground temperature variations are more significant than air temperature changes. Also, the graph shows that the response of the ground temperature to solar radiation is more intense than that of air temperature. The plot of the daily pressure change on Mars shows that the MSL broadcast pressure variations on Mars are up to 15% of total atmospheric pressure.
Initial REMS data was not what teams expected which was the first sign of a larger problem associated with the REMS Instrument. During REMS checkouts, it was found that the boom looking to the side was sending saturated wind data at either high or low levels which was not valid. The issue was traced back to the exposed circuit boards of the REMS Wind Sensor and it was determined that two of three boards on the boom in question had damaged wiring. Teams assessed the situation and came to the conclusion that this type of damage was permanent without a chance of recovery. The REMS instrument and its wind sensors were successfully checked during cruise so that instrument health following launch and ascent aboard the Atlas V rocket back in November 2011 was confirmed.
With the instruments starting to send bad data after landing while functioning during cruise has led to teams assuming that the instrument's circuit boards were damaged during Entry, Descent and Landing.
Ashwin Vasavada, Curiosity deputy project scientist, has stressed that there is now way (typo -correction - no way) of finding out what exactly happened to the hardware, but that teams have developed the hypothesis of small rocks damaging the tiny wires of the circuit boards during the propulsive landing. Following landing, images have shown small pebbles on the Rover Deck that were picked up by the Mars Landing Engines while the Descent Stage was hovering above Curiosity during landing.
Possibly, these pebbles could have hit the fragile hardware on the mast which was in its stowed position with the REMS booms facing outward, leading to the damage teams are seeing. With this permanent damage on their sensors, the REMS team had to start the process of learning how to take satisfactory wind data with one degraded sensor. Luckily, REMS has wind sensors on both of its booms so that there was still the option of returning sufficient wind data to meet the science objectives of the instrument. Comment – all REMS daily weather reports published up until October 18, 2012 show wind from the east at 2 m/s (7.2 km/h). This wind is not anywhere near the velocity required to move sand dunes or to fill in rover tracks as is discussed elsewhere on my son's web site at MOVING SAND AND MARTIAN WIND. Further, the data will be suspect until there is some variation in direction or wind strength seen.
After instrument commissioning was complete, REMS began nominal operations, performing 5 minutes of data acquisition during each hour on Mars with 60 additional minutes of each Sol for scheduled observations and event-triggered instrument operation. Suggestion: For ease of comparison, adopt the system used for Viking 1 and 2. There each was sol was divided into 25 time bins, each a little over 59 minutes long. See the presentation method at http://www-k12.atmos.washington.edu/k12/mars/data/vl1/segment1.html, but be sure that data published is easy to transfer to spreadsheets for further analysis.
Landing on Mars in early August placed MSL in the late northern-Summer Season on the planet. True, but because MSL was south of the equator, it was late winter there.
The average pressure detected during the first 19 Sols on Mars was 730Pa which was as expected. The pressure on Mars shows a daily variation and a seasonal variation. The seasonal change is caused by Carbon Dioxide being converted into its solid phase at the Poles according to a seasonal cycle – meaning that gaseous CO2 is removed from the atmosphere resulting in a loss of total atmospheric mass and pressure. Comment – This is as has been widely accepted since the Viking missions. However, it supposes that the Viking pressure curves are correct and that they reflect ambient atmospheric conditions. We challenge that assumption, believing that just as landing conditions knocked out at least one wind boom on MSL, the dust clogged all dust filters and left transducers to measure pressure changes all due to RTGs on the Vikings and Pathfinder, or the steady drop in pressure as the temperature fell on Phoenix where there was no RTG. As Figure 6D shows above, there is an extremely suspect link seen again on MSL between falling temperatures and rising pressures. This is properly seen on Figure 6B, but shown with an inverted pressure curve on Figure 6D to emphasize how very similar the relationship appears to be. We are therefore confident that the pressures being transmitted from Mars do not correspond to actual ambient pressure.
Carbon Dioxide is a major component of the Martian Atmosphere (95%). The daily variation of pressure with a minimum of 685 and a maximum of nearly 785Pa during the first Sols is caused by tides. Martian tides cannot be compared to tides on Earth which are caused by the gravitational force of the Moon. On Mars, tides are large atmospheric scale waves that are caused by heating due to the sun. These tides are sensitive to the distribution of clouds and atmospheric dust as well as a large-scale pattern of jet-stream like winds.
During the first Sols, REMS also detected smaller pressure variations which could have been caused by minor atmospheric flows within the Gale Crater System, but more data is required to analyze these small localized phenomena.